George W. Bartelmez 



75 



§ 12 

 0£ the formation of albumen and chala/.ae. 



I turn now to the later stages in the formation of the egg. At the 

 upper end of the oviduct, where the longitudinal folds of ilic mucous 

 membrane begin, a first thin layer of albumen appears enswaihing 

 the vitelline membrane; at opposite ends where the oviduct is con- 

 stricted above and below [the ovum], soft, clear, albuminous nodules 

 are laid down, from which on both sides a strand of albumen is con- 

 tinued, surrounded by the folds of the internal lamina of the oviduct; 

 these strands are the rudiments of the chalazae (fig. 21). Up to this 

 time there is no hint of the white twisted strands which occupy the 

 center of the fully developed chalazae, nor is the vitelline membrane 

 as yet marked by radial folds through the twisting of the chalazae. 

 Now, as the yolk is moved along by the peristalsis of the oviduct, layer 

 upon layer of albumen secreted by the walls is added in the form of a 

 spiral band. Meanwhile, the first lamina of albumen begins to thicken 

 against the yolk and is converted into a rather firm envelope, adher- 

 ing very closely to the vitelline membrane. From this envelope the 

 internal whitish strands of the chalazae extend. The yolk with the 

 surrounding albumen is movable about its [longest] axis. The chalazae 

 attached to the membrane [of chalaziferous albumen] are produced 

 [] 16 ] by twisting, as a thread is spun from a distaff and twisted upon itself 

 again and again. Accordingly you will also find spirally wound layers 

 on the very surface of the albumen which is subsecjuently laid down. 

 It ^\'ill be most obvious that this is not a figment of the imagination if 

 yoti will take out an egg already fully surrounded by albumen from 

 near the lowest part of the oviduct and study it after about an hour's 

 immersion in perfectly fresh cold spring water. The albumen which 

 was at first clear and transparent is gradually made turbid and opales- 

 cent by the water and shows strands on its surface which run spirally 

 from left to right proceeding from the blunt to the more pointed end. 

 If you tease them away with volsella forceps, they come off in lamellae 

 all runnina: in the same direction until the whole albumen is un- 

 wound down to the chalazae (fig. 22). Now Avhen you have come 

 almost to the chalazal membrane which covers the yolk, the last layers 

 are very soft, so that you almost think the space empty; the rest of tiie 

 albumen passes to the chalazae and hangs like a hood from them. 

 From these facts it may be inferred that Fabricius ab Aquapendente 

 proposed a perfecdy correct interpretation of the formation of albu- 

 men and chalazae, and no one should believe that they arise from 

 the vitelline membrane and grow like plants.*""' 



